The present invention is directed to an apparatus for making a plastic bag that has a zip type opening that extends across a portion of the top of the bag and the remaining portion of the top of the bag being permanently sealed. The present invention is also directed to the plastic bag itself and the method for making such a plastic bag. More particularly, the invention concerns the use of a vertical form, fill and seal machine for producing and method of making improved reclosable plastic bags on such a machine that when the plastic bag is opened it has a pour spout. A vertical form, fill and seal machine of the type that could be used, in conjunction with a unique change part, for this invention is disclosed in U.S. Pat. No. 5,715,656 that issued on Feb. 10, 1998, which patent is hereby included by reference as a part of this disclosure.
Conventional vertical form, fill and seal packaging machines have been used in a number of ways to accommodate the introduction of a zipper component to thus produce a reclosable package or bag. Reclosable packages including zippered seal have the advantage that they can be zipped closed after having been initially opened. For example, a restaurant might purchase a large capacity bag, having a zipper seal, of frozen French fries, open the package, remove a portion of the contents and then reseal the package and store it in a freezer for future use.
Some reclosable bags produced on vertical form-fill-and-seal machines, produced a plastic package having a zipper connector bonded within the vertical edge seal. The vertical edge, containing the zipper connector, then serves as the top of the filled package.
Conventional vertical form, fill and seal packaging machines, such as that disclosed in U.S. Pat. No. 5,425,216, have been modified to produce reclosable bags by securing the unconnected interlocking members of a zipper connection to the inner surface of a loop formed in the film from which the bag is produced. However, this system requires additional steps to merge the unconnected interlocking members into alignment and then interlock them.
A method of making reclosable bags is disclosed in U.S. Pat. Nos. 4,655,862 and 4,909,017 in which a strip of fastener material is bonded to the film material from which the bag is to be formed before the film reaches the form, fill and seal machine. The strip of fastener material, that is secured to the web includes both halves of the interlocked zipper fastener. The backing strip for only one of zipper components is bonded to the web before the bag forming process commences. The backing strip for the other zipper component is sealed to the film during the cross sealing step of the bag formation. This system of producing reclosable packages has the following problems.
The machine used to bond the strip of fastener material to the film interferes with the necessary servicing of the form, fill and seal machine. The speed of the form, fill and seal machine is limited by the speed of the machine for bonding the strip of fastener to the film. The speed of existing machines for bonding the zip-lock material to the film is slow compared to the potential speed of most modern form, fill and seal machines. Anther problem with the prior art machines is that it is difficult to coordinate the machine that bonds the zip-lock material to the film and the form, fill and seal machine such that the zip-lock material is properly located on the film relative to where the cross seal is formed and the printout carried by the film. Furthermore, existing reclosable bags have a reclosable mechanism that extends across the complete top edge of the bag. It is difficult to pour or meter out the contents of the bag when the bag is open across its complete top edge. Attempts to form a pouring spout by partially closing zipper fastener are not successful since the pressure of the contents being poured or metered out of the bag forces the zipper fastener to open.
An apparatus that can be used to produce the unique packages of this invention has been developed by the inventor of this application and a separate application disclosing and claiming that apparatus is being filed on the same day as this application. The sole inventor of that application is John M. Linkiewicz and the title of that application is ZIPPER SEALER MACHINE. This application is by reference hereby included as a part of this disclosure.
For the foregoing reasons, there is a need for a machine and method for producing plastic bags that have reclosable portions that extend across only a portion of the top of the bag such that when opened the bag has a pouring spout that will restrict and constrain the product contained in the bag from flowing from the bag at an uncontrolled rate.